The general direction of this research is an understanding of aspects of processing of RNA in mammalian cells. We are investigating the role of specific proteins in the maturation of nucleolar ribosomal precursor particles, and of nuclear heterogeneous RNA particles. The use of temperature sensitive mutant cells and viruses is being exploited in these studies. BIBLIOGRAPHIC REFERENCES: Krug, R.M. and Soeiro, R. Studies on the Intranuclear Localization of Influenza Virus - Specific Proteins. Virology, 64:378-387, 1975.